The invention relates generally to imaging systems, and more specifically to a system and method for a radiation imaging system.
Radiation systems like tomosynthesis systems are often used in the field of medicine to generate three-dimensional (3D) images of an object. Typically, tomosynthesis systems include X-ray systems and computer tomography systems. A typical tomosynthesis system comprises an X-ray source, an X-ray detector and a processing circuit. The X-ray source is either stationary or is rotated on an arc and projects X-rays on the object, usually a patient. The X-rays are filtered by a collimator subsequent to passing through the object being scanned. The attenuated beams are then detected by a set of detector elements.
Typically, the detector comprises X-ray detecting media such as scintillators disposed over an optical detector usually comprising an array of photosensitive elements. The attenuated X-ray beams are first detected by the scintillators, which convert the X-ray beams to visible photons. The photosensitive elements detect the visible photons and convert to corresponding electrical signals based on the intensity of the attenuated X-ray beams, and the signals are processed to produce projections. By using reconstruction techniques three-dimensional images are formed from these projections.
One problem with such an arrangement of the detector is the transmission of the electrical signals from the rotating gantry. In particular, maintaining signal fidelity of a large quantity of un-amplified electrical signals in a noisy (EMI, EMC from adjacent motors, fans, etc.) electrical environment presents challenges to the current detector arrangement. In addition, the mechanical aspects of the gantry operation impose vibration and transient acceleration that can further lead to electrical signal degradation (microphonics, et. al.).
Another typical problem with the detector is that the response of the photosensitive elements is temperature-dependent. It would be desirable to design a detector in a way such that the heat produced in the amplification and signal processing components does not affect the performance of the photosensitive elements.
For imaging, it is desirable to transmit a large number of parallel signals, either to accommodate a larger field of view, or to improve resolution through smaller pixel size, resulting in higher quality images. Significant mechanical and electrical challenges are inherent in maintaining signal integrity through the transmission and processing of these parallel signals; In addition, the readout time of image/signal is proportionally increased.
In addition, while designing the detector, great care has to be taken in selecting the scintillator material such that the wavelength of the photons generated by the scintillator matches the peak sensitivity of the photosensitive element. As a result, other scintillator material properties, e.g., conversion efficiency (i.e. gain) and intrinsic decay may be sub-optimal. The opportunity to utilize scintillators that output multiple wavelengths is also limited.
It would therefore be desirable to design an imaging system where the X-ray detecting media can be optimized for its optical performance, manufacturability, and ease of integration with the X-ray imaging system. In addition, it would be desirable to design an imaging system that utilizes optical channels to provide for high signal bandwidth and to eliminate the limitations inherent in traditional electrical interconnect.